Her spokeswoman told Metro.co.uk that she wants to make sure she can handle 48 live concerts when her shows kick off at the 4,600-seater Planet Hollywood venue in December.
Spears will rake in 200,000 pounds a night for her shows.
Earlier she was accused of being paid a lot of money just to lip-sync.
The insider told the New York Daily News that the 'Toxic' hitmaker hasn't sung live for a couple of years.
--ANI (Posted on 25-09-2013)